Anaerobic digestion of residual lignocellulosic materials to biogas and biohydrogen

Arundo donax (giant reed) hydrolysate was exploited as a substrate for anaerobic digestion aimed to the production of biogas and biohydrogen. A mixed culture adapted from a primary sludge digester was used as inoculum. Besides the biogas, the anaerobic fermentation products were ethanol, acetic acid and butyric acid. Together, the soluble products accounted for about 51 % of degraded carbon. The produced biogas was 5 % H2, 41 % CO2 and 54 % CH4 by volume. Fermentation kinetics was slower and biogas yields were lower than those found with glucose fermentation with same mixed culture. Further optimization of the process is envisaged in order to improve biohydrogen yield.